Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Data Link References
This table identifies which serial data link that a particular device uses for in-vehicle data transmission. Some devices may use more than one data link to communicate. Some devices may have multiple communication circuits passing through them without actively communicating on that data link. This table is used to assist in correcting a communication malfunction. Not all devices listed will be applicable to all vehicles. Refer to the Wiring Schematics to determine which devices apply. For the description and operation of these serial data communication circuits, refer to Data Link Communications Description and Operation .
| Code | Device | Data Link Type | Diagnostic Procedure |
|---|---|---|---|
| Schematic Reference: Data Communication Wiring Schematics | |||
| A11 | Radio | Gateway Isolated Low Speed GMLAN | DTC U007D |
| B99 | Steering Wheel Angle Sensor | Chassis High Speed GMLAN | DTC U0077 |
| B174W | Frontview Camera - Windshield | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| K9 | Body Control Module |
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| K17 | Electronic Brake Control Module |
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| K20 | Engine Control Module | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device |
| K29 | Seat Heating Control Module | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| K33 | HVAC Control Module | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| K36 | Inflatable Restraint Sensing and Diagnostic Module |
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| K38 | Chassis Control Module | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device |
| K43 | Power Steering Control Module | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device |
| K56 | Serial Data Gateway Module |
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| K60 | Steering Column Lock Module | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| K71 / Q8 / T12 | Transmission Control Module / Control Solenoid Valve Assembly / Automatic Transmission Assembly | High Speed GMLAN | Scan Tool Does Not Communicate with High Speed GMLAN Device |
| K73 | Telematics Communication Interface Control Module |
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| K84 | Keyless Entry Control Module | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| K85 | Passenger Presence Module | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| K182 | Parking Assist Control Module | Low Speed GMLAN | Scan Tool Does Not Communicate with Low Speed GMLAN Device |
| M74D | Window Motor - Driver | Local Interconnect Network (LIN) | DTC U1500-U15FF |
| M74P | Window Motor - Passenger | Local Interconnect Network (LIN) | DTC U1500-U15FF |
| P16 | Instrument Cluster |
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| S79LR | Window Switch - Left Rear | Local Interconnect Network (LIN) | DTC U1500-U15FF |
| S79RR | Window Switch - Right Rear | Local Interconnect Network (LIN) | DTC U1500-U15FF |
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.